// tutorial07.c
// A pedagogical video player that really works! Now with seeking features.
//
// This tutorial was written by Stephen Dranger (dranger@gmail.com).
//
// Code based on FFplay, Copyright (c) 2003 Fabrice Bellard, 
// and a tutorial by Martin Bohme (boehme@inb.uni-luebeckREMOVETHIS.de)
// Tested on Gentoo, CVS version 5/01/07 compiled with GCC 4.1.1
//
// Use the Makefile to build all the samples.
//
// Run using
// tutorial07 myvideofile.mpg
//
// to play the video.

#include "libavcodec/avcodec.h"
#include "libavformat/avformat.h"
#include "libavformat/avio.h"
#include "libswscale/swscale.h"
#include "libavutil/avstring.h"
#include "libavutil/time.h"
#include "SDL.h"
#include "SDL_thread.h"

#include <stdio.h>
#include <math.h>

#ifdef __MINGW32__
#undef main /* Prevents SDL from overriding main() */
#endif


#define SDL_AUDIO_BUFFER_SIZE 1024
#define MAX_AUDIO_FRAME_SIZE 192000
#define MAX_AUDIOQ_SIZE (5 * 16 * 1024)
#define MAX_VIDEOQ_SIZE (5 * 256 * 1024)
#define AV_SYNC_THRESHOLD 0.01
#define AV_NOSYNC_THRESHOLD 10.0
#define SAMPLE_CORRECTION_PERCENT_MAX 10
#define AUDIO_DIFF_AVG_NB 20
#define FF_ALLOC_EVENT   (SDL_USEREVENT)
#define FF_REFRESH_EVENT (SDL_USEREVENT + 1)
#define FF_QUIT_EVENT (SDL_USEREVENT + 2)
#define VIDEO_PICTURE_QUEUE_SIZE 1
#define DEFAULT_AV_SYNC_TYPE AV_SYNC_VIDEO_MASTER

typedef struct PacketQueue 
{
	AVPacketList *first_pkt, *last_pkt;
	int nb_packets;
	int size;
	SDL_mutex *mutex;
	SDL_cond *cond;
} PacketQueue;

typedef struct VideoPicture 
{
	SDL_Overlay *bmp;
	int width;
	int height; /* source height & width */
	int allocated;
	double pts;
} VideoPicture;

typedef struct VideoState 
{
	AVFormatContext *pFormatCtx;
	int             videoStream, audioStream;

	int             av_sync_type;
	double          external_clock; /* external clock base */
	int64_t         external_clock_time;

	int             seek_req;
	int             seek_flags;
	int64_t         seek_pos;

	double          audio_clock;
	AVStream        *audio_st;
	PacketQueue     audioq;
	AVFrame         audio_frame;
	uint8_t         audio_buf[(MAX_AUDIO_FRAME_SIZE * 3) / 2];
	unsigned int    audio_buf_size;
	unsigned int    audio_buf_index;
	AVPacket        audio_pkt;
	uint8_t         *audio_pkt_data;
	int             audio_pkt_size;
	int             audio_hw_buf_size;  
	double      audio_diff_cum; /* used for AV difference average computation */
	double      audio_diff_avg_coef;
	double      audio_diff_threshold;
	int             audio_diff_avg_count;

	double          frame_timer;
	double          frame_last_pts;
	double          frame_last_delay;
	double          video_clock; ///<pts of last decoded frame / predicted pts of next decoded frame
	double          video_current_pts; ///<current displayed pts (different from video_clock if frame fifos are used)
	int64_t         video_current_pts_time;  ///<time (av_gettime) at which we updated video_current_pts - used to have running video pts
	AVStream        *video_st;
	PacketQueue     videoq;
	VideoPicture    pictq[VIDEO_PICTURE_QUEUE_SIZE];
	int    pictq_size;
	int    pictq_rindex;
	int    pictq_windex;

	SDL_mutex       *pictq_mutex;
	SDL_cond        *pictq_cond;
	SDL_Thread      *parse_tid;
	SDL_Thread      *video_tid;

	char          filename[1024];
	int             quit;

	AVIOContext     *io_context;
	struct SwsContext *sws_ctx;

} VideoState;

enum {
	AV_SYNC_AUDIO_MASTER,
	AV_SYNC_VIDEO_MASTER,
	AV_SYNC_EXTERNAL_MASTER,
};

SDL_Surface     *screen;

/* Since we only have one decoding thread, the Big Struct
can be global in case we need it. */
VideoState *global_video_state;
AVPacket flush_pkt;

void packet_queue_init(PacketQueue *q) {
	memset(q, 0, sizeof(PacketQueue));
	q->mutex = SDL_CreateMutex();
	q->cond = SDL_CreateCond();
}

int packet_queue_put(PacketQueue *q, AVPacket *pkt)
{
	AVPacketList *pkt1;
	if(pkt != &flush_pkt && av_dup_packet(pkt) < 0) {
		return -1;
	}

	pkt1 = av_malloc(sizeof(AVPacketList));
	if (!pkt1)  return -2;

	pkt1->pkt = *pkt;
	pkt1->next = NULL;

	SDL_LockMutex(q->mutex);

	if (!q->last_pkt)
		q->first_pkt = pkt1;
	else
		q->last_pkt->next = pkt1;

	q->last_pkt = pkt1;
	q->nb_packets++;
	q->size += pkt1->pkt.size;
	SDL_CondSignal(q->cond);

	SDL_UnlockMutex(q->mutex);
	return 0;
}

static int packet_queue_get(PacketQueue *q, AVPacket *pkt, int block)
{
	AVPacketList *pkt1;
	int ret;

	SDL_LockMutex(q->mutex);

	for(;;) {

		if(global_video_state->quit) {
			ret = -1;
			break;
		}

		pkt1 = q->first_pkt;
		if (pkt1) 
		{
			q->first_pkt = pkt1->next; 
			if (!q->first_pkt) q->last_pkt = NULL;

			q->nb_packets--;
			q->size -= pkt1->pkt.size;
			*pkt = pkt1->pkt;
			av_free(pkt1);
			ret = 1;
			break;
		} 
		else if (!block) {
			ret = 0;
			break;
		} 
		else {
			SDL_CondWait(q->cond, q->mutex);
		}
	}
	SDL_UnlockMutex(q->mutex);
	return ret;
}
static void packet_queue_flush(PacketQueue *q) {
	AVPacketList *pkt, *pkt1;

	SDL_LockMutex(q->mutex);
	for(pkt = q->first_pkt; pkt != NULL; pkt = pkt1) {
		pkt1 = pkt->next;
		av_free_packet(&pkt->pkt);
		av_freep(&pkt);
	}
	q->last_pkt = NULL;
	q->first_pkt = NULL;
	q->nb_packets = 0;
	q->size = 0;
	SDL_UnlockMutex(q->mutex);
}

double get_audio_clock(VideoState *is) 
{
	double pts;
	int hw_buf_size, bytes_per_sec, n;

	pts = is->audio_clock; /* maintained in the audio thread */
	hw_buf_size = is->audio_buf_size - is->audio_buf_index;
	bytes_per_sec = 0;
	n = is->audio_st->codec->channels * 2;
	if(is->audio_st) {
		bytes_per_sec = is->audio_st->codec->sample_rate * n;
	}
	if(bytes_per_sec) {
		pts -= (double)hw_buf_size / bytes_per_sec;
	}
	return pts;
}

double get_video_clock(VideoState *is) 
{
	double delta;

	delta = (av_gettime() - is->video_current_pts_time) / 1000000.0;
	return is->video_current_pts + delta;
}

double get_external_clock(VideoState *is) 
{
	return av_gettime() / 1000000.0;
}

double get_master_clock(VideoState *is) 
{
	if(is->av_sync_type == AV_SYNC_VIDEO_MASTER) {
		return get_video_clock(is);
	} 
	else if(is->av_sync_type == AV_SYNC_AUDIO_MASTER) {
		return get_audio_clock(is);
	} 
	else {
		return get_external_clock(is);
	}
}

/* Add or subtract samples to get a better sync, return new
audio buffer size */
int synchronize_audio(VideoState *is, short *samples,
	int samples_size, double pts) 
{
	int n;
	double ref_clock;

	n = 2 * is->audio_st->codec->channels;

	if(is->av_sync_type != AV_SYNC_AUDIO_MASTER) 
	{
		double diff, avg_diff;
		int wanted_size, min_size, max_size /*, nb_samples */;

		ref_clock = get_master_clock(is);
		diff = get_audio_clock(is) - ref_clock;

		if(diff < AV_NOSYNC_THRESHOLD) 
		{
			// accumulate the diffs
			is->audio_diff_cum = diff + is->audio_diff_avg_coef * is->audio_diff_cum;
			if(is->audio_diff_avg_count < AUDIO_DIFF_AVG_NB) 
			{
				is->audio_diff_avg_count++;
			} 
			else 
			{
				avg_diff = is->audio_diff_cum * (1.0 - is->audio_diff_avg_coef);
				if(fabs(avg_diff) >= is->audio_diff_threshold) 
				{
					wanted_size = samples_size + ((int)(diff * is->audio_st->codec->sample_rate) * n);
					min_size = samples_size * ((100 - SAMPLE_CORRECTION_PERCENT_MAX) / 100);
					max_size = samples_size * ((100 + SAMPLE_CORRECTION_PERCENT_MAX) / 100);

					if(wanted_size < min_size) {
						wanted_size = min_size;
					} 
					else if (wanted_size > max_size) {
						wanted_size = max_size;
					}

					if(wanted_size < samples_size) {
						/* remove samples */
						samples_size = wanted_size;
					} 
					else if(wanted_size > samples_size) {
						uint8_t *samples_end, *q;
						int nb;

						/* add samples by copying final sample*/
						nb = (samples_size - wanted_size);
						samples_end = (uint8_t *)samples + samples_size - n;
						q = samples_end + n;
						while(nb > 0) {
							memcpy(q, samples_end, n);
							q += n;
							nb -= n;
						}
						samples_size = wanted_size;
					}

				}
			}
		} 
		else {
			/* difference is TOO big; reset diff stuff */
			is->audio_diff_avg_count = 0;
			is->audio_diff_cum = 0;
		}
	}
	return samples_size;
}

int audio_decode_frame(VideoState *is, double *pts_ptr) 
{
	int len1, data_size = 0, n;
	AVPacket *pkt = &is->audio_pkt;
	double pts;

	for(;;) 
	{
		while(is->audio_pkt_size > 0) 
		{
			int got_frame = 0;
			len1 = avcodec_decode_audio4(is->audio_st->codec, &is->audio_frame, &got_frame, pkt);
			if(len1 < 0) 
			{
				/* if error, skip frame */
				is->audio_pkt_size = 0;
				break;
			}

			if (got_frame)
			{
				data_size =  av_samples_get_buffer_size  ( NULL,  is->audio_st->codec->channels,
					is->audio_frame.nb_samples, is->audio_st->codec->sample_fmt, 1);
				memcpy(is->audio_buf, is->audio_frame.data[0], data_size);
			}
			is->audio_pkt_data += len1;
			is->audio_pkt_size -= len1;
			if(data_size <= 0) 
			{
				/* No data yet, get more frames */
				continue;
			}
			pts = is->audio_clock;
			*pts_ptr = pts;
			n = 2 * is->audio_st->codec->channels;
			is->audio_clock += (double)data_size /
				(double)(n * is->audio_st->codec->sample_rate);

			/* We have data, return it and come back for more later */
			return data_size;
		}

		if(pkt->data)
			av_free_packet(pkt);

		if(is->quit) 
		{
			return -1;
		}
		/* next packet */
		if(packet_queue_get(&is->audioq, pkt, 1) < 0) {
			return -1;
		}

		if(pkt->data == flush_pkt.data) {
			avcodec_flush_buffers(is->audio_st->codec);
			continue;
		}

		is->audio_pkt_data = pkt->data;
		is->audio_pkt_size = pkt->size;
		/* if update, update the audio clock w/pts */
		if(pkt->pts != AV_NOPTS_VALUE) {
			is->audio_clock = av_q2d(is->audio_st->time_base)*pkt->pts;
		}

	}
}

void audio_callback(void *userdata, Uint8 *stream, int len) 
{
	VideoState *is = (VideoState *)userdata;
	int len1;
	int audio_size;
	double pts;

	while(len > 0) 
	{
		if(is->audio_buf_index >= is->audio_buf_size) 
		{
			/* We have already sent all our data; get more */
			audio_size = audio_decode_frame(is, &pts);
			if(audio_size < 0) {
				/* If error, output silence */
				is->audio_buf_size = 1024;
				memset(is->audio_buf, 0, is->audio_buf_size);
			} 
			else {
				audio_size = synchronize_audio(is, (int16_t *)is->audio_buf, audio_size, pts);
				is->audio_buf_size = audio_size;
			}
			is->audio_buf_index = 0;
		}
		len1 = is->audio_buf_size - is->audio_buf_index;
		if(len1 > len)
			len1 = len;

		memcpy(stream, (uint8_t *)is->audio_buf + is->audio_buf_index, len1);
		len -= len1;
		stream += len1;
		is->audio_buf_index += len1;
	}
}

static Uint32 sdl_refresh_timer_cb(Uint32 interval, void *opaque) 
{
	SDL_Event event;
	event.type = FF_REFRESH_EVENT;
	event.user.data1 = opaque;
	SDL_PushEvent(&event);
	return 0; /* 0 means stop timer */
}

/* schedule a video refresh in 'delay' ms */
static void schedule_refresh(VideoState *is, int delay) 
{
	SDL_AddTimer(delay, sdl_refresh_timer_cb, is);
}

void video_display(VideoState *is) 
{
	SDL_Rect rect;
	VideoPicture *vp;
	//AVPicture pict;
	float aspect_ratio;
	int w, h, x, y;
	//int i;

	vp = &is->pictq[is->pictq_rindex];
	if(vp->bmp) 
	{
		if(is->video_st->codec->sample_aspect_ratio.num == 0) 
		{
			aspect_ratio = 0;
		} 
		else 
		{
			aspect_ratio = av_q2d(is->video_st->codec->sample_aspect_ratio) *
				is->video_st->codec->width / is->video_st->codec->height;
		}

		if(aspect_ratio <= 0.0) {
			aspect_ratio = (float)is->video_st->codec->width /
				(float)is->video_st->codec->height;
		}

		h = screen->h;
		w = ((int)rint(h * aspect_ratio)) & -3;

		if(w > screen->w) {
			w = screen->w;
			h = ((int)rint(w / aspect_ratio)) & -3;
		}

		x = (screen->w - w) / 2;
		y = (screen->h - h) / 2;

		rect.x = x;
		rect.y = y;
		rect.w = w;
		rect.h = h;
		SDL_DisplayYUVOverlay(vp->bmp, &rect);
	}
}

void video_refresh_timer(void *userdata) 
{

	VideoState *is = (VideoState *)userdata;
	VideoPicture *vp;
	double actual_delay, delay, sync_threshold, ref_clock, diff;

	if(is->video_st) 
	{
		if(is->pictq_size == 0) {
			schedule_refresh(is, 1);
		} 
		else {
			vp = &is->pictq[is->pictq_rindex];

			is->video_current_pts = vp->pts;
			is->video_current_pts_time = av_gettime();

			delay = vp->pts - is->frame_last_pts; /* the pts from last time */
			if(delay <= 0 || delay >= 1.0) {
				/* if incorrect delay, use previous one */
				delay = is->frame_last_delay;
			}

			/* save for next time */
			is->frame_last_delay = delay;
			is->frame_last_pts = vp->pts;

			/* update delay to sync to audio if not master source */
			if(is->av_sync_type != AV_SYNC_VIDEO_MASTER) 
			{
				ref_clock = get_master_clock(is);
				diff = vp->pts - ref_clock;

				/* Skip or repeat the frame. Take delay into account
				FFPlay still doesn't "know if this is the best guess." */
				sync_threshold = (delay > AV_SYNC_THRESHOLD) ? delay : AV_SYNC_THRESHOLD;
				if(fabs(diff) < AV_NOSYNC_THRESHOLD)
				{
					if(diff <= -sync_threshold) {
						delay = 0;
					} 
					else if(diff >= sync_threshold) {
						delay = 2 * delay;
					}
				}
			}

			is->frame_timer += delay;
			/* computer the REAL delay */
			actual_delay = is->frame_timer - (av_gettime() / 1000000.0);
			if(actual_delay < 0.010) {
				/* Really it should skip the picture instead */
				actual_delay = 0.010;
			}
			schedule_refresh(is, (int)(actual_delay * 1000 + 0.5));

			/* show the picture! */
			video_display(is);

			/* update queue for next picture! */
			if(++is->pictq_rindex == VIDEO_PICTURE_QUEUE_SIZE) {
				is->pictq_rindex = 0;
			}
			SDL_LockMutex(is->pictq_mutex);
			is->pictq_size--;
			SDL_CondSignal(is->pictq_cond);
			SDL_UnlockMutex(is->pictq_mutex);
		}
	} else {
		schedule_refresh(is, 100);
	}
}

void alloc_picture(void *userdata) 
{
	VideoState *is = (VideoState *)userdata;
	VideoPicture *vp;

	vp = &is->pictq[is->pictq_windex];
	if(vp->bmp) {
		// we already have one make another, bigger/smaller
		SDL_FreeYUVOverlay(vp->bmp);
	}
	// Allocate a place to put our YUV image on that screen
	vp->bmp = SDL_CreateYUVOverlay(is->video_st->codec->width,
		is->video_st->codec->height,
		SDL_YV12_OVERLAY,
		screen);
	vp->width = is->video_st->codec->width;
	vp->height = is->video_st->codec->height;

	SDL_LockMutex(is->pictq_mutex);
	vp->allocated = 1;
	SDL_CondSignal(is->pictq_cond);
	SDL_UnlockMutex(is->pictq_mutex);
}

int queue_picture(VideoState *is, AVFrame *pFrame, double pts) 
{
	VideoPicture *vp;
	//int dst_pix_fmt;
	AVPicture pict;

	/* wait until we have space for a new pic */
	SDL_LockMutex(is->pictq_mutex);
	while(is->pictq_size >= VIDEO_PICTURE_QUEUE_SIZE && !is->quit) {
		SDL_CondWait(is->pictq_cond, is->pictq_mutex);
	}
	SDL_UnlockMutex(is->pictq_mutex);

	if(is->quit)
		return -1;

	// windex is set to 0 initially
	vp = &is->pictq[is->pictq_windex];

	/* allocate or resize the buffer! */
	if(!vp->bmp || vp->width != is->video_st->codec->width ||
		vp->height != is->video_st->codec->height) 
	{
		SDL_Event event;

		vp->allocated = 0;
		/* we have to do it in the main thread */
		event.type = FF_ALLOC_EVENT;
		event.user.data1 = is;
		SDL_PushEvent(&event);

		/* wait until we have a picture allocated */
		SDL_LockMutex(is->pictq_mutex);
		while(!vp->allocated && !is->quit) 
		{
			SDL_CondWait(is->pictq_cond, is->pictq_mutex);
		}
		SDL_UnlockMutex(is->pictq_mutex);
		if(is->quit) {
			return -1;
		}
	}
	/* We have a place to put our picture on the queue */
	/* If we are skipping a frame, do we set this to null 
	but still return vp->allocated = 1? */


	if(vp->bmp) {

		SDL_LockYUVOverlay(vp->bmp);

		//dst_pix_fmt = PIX_FMT_YUV420P;
		/* point pict at the queue */

		pict.data[0] = vp->bmp->pixels[0];
		pict.data[1] = vp->bmp->pixels[2];
		pict.data[2] = vp->bmp->pixels[1];

		pict.linesize[0] = vp->bmp->pitches[0];
		pict.linesize[1] = vp->bmp->pitches[2];
		pict.linesize[2] = vp->bmp->pitches[1];

		// Convert the image into YUV format that SDL uses
		sws_scale ( is->sws_ctx, (uint8_t const * const *)pFrame->data, pFrame->linesize,
			0,  is->video_st->codec->height,  pict.data,  pict.linesize );

		SDL_UnlockYUVOverlay(vp->bmp);
		vp->pts = pts;

		/* now we inform our display thread that we have a pic ready */
		if(++is->pictq_windex == VIDEO_PICTURE_QUEUE_SIZE) 
		{
			is->pictq_windex = 0;
		}
		SDL_LockMutex(is->pictq_mutex);
		is->pictq_size++;
		SDL_UnlockMutex(is->pictq_mutex);
	}
	return 0;
}

double synchronize_video(VideoState *is, AVFrame *src_frame, double pts) 
{
	double frame_delay;

	if(pts != 0) {
		/* if we have pts, set video clock to it */
		is->video_clock = pts;
	} 
	else {
		/* if we aren't given a pts, set it to the clock */
		pts = is->video_clock;
	}

	/* update the video clock */
	frame_delay = av_q2d(is->video_st->codec->time_base);
	/* if we are repeating a frame, adjust clock accordingly */
	frame_delay += src_frame->repeat_pict * (frame_delay * 0.5);
	is->video_clock += frame_delay;
	return pts;
}

uint64_t global_video_pkt_pts = AV_NOPTS_VALUE;

/* These are called whenever we allocate a frame
* buffer. We use this to store the global_pts in
* a frame at the time it is allocated.
*/
int our_get_buffer(struct AVCodecContext *c, AVFrame *pic) 
{
	int ret = avcodec_default_get_buffer(c, pic);
	uint64_t *pts = av_malloc(sizeof(uint64_t));
	*pts = global_video_pkt_pts;
	pic->opaque = pts;
	return ret;
}

void our_release_buffer(struct AVCodecContext *c, AVFrame *pic) 
{
	if(pic) av_freep(&pic->opaque);
	avcodec_default_release_buffer(c, pic);
}

int video_thread(void *arg) 
{
	VideoState *is = (VideoState *)arg;
	AVPacket pkt1, *packet = &pkt1;
	int frameFinished;
	AVFrame *pFrame;
	double pts;

	pFrame = avcodec_alloc_frame();

	for(;;) {
		if(packet_queue_get(&is->videoq, packet, 1) < 0) {
			// means we quit getting packets
			break;
		}
		if(packet->data == flush_pkt.data) {
			avcodec_flush_buffers(is->video_st->codec);
			continue;
		}
		pts = 0;

		// Save global pts to be stored in pFrame in first call
		global_video_pkt_pts = packet->pts;
		// Decode video frame
		avcodec_decode_video2(is->video_st->codec, pFrame, &frameFinished, packet);

		if(packet->dts == AV_NOPTS_VALUE 
			&& pFrame->opaque && *(uint64_t*)pFrame->opaque != AV_NOPTS_VALUE) {
				pts = *(uint64_t *)pFrame->opaque;
		} 
		else if(packet->dts != AV_NOPTS_VALUE) {
			pts = packet->dts;
		} 
		else {
			pts = 0;
		}
		pts *= av_q2d(is->video_st->time_base);

		// Did we get a video frame?
		if(frameFinished) {
			pts = synchronize_video(is, pFrame, pts);
			if(queue_picture(is, pFrame, pts) < 0) {
				break;
			}
		}
		av_free_packet(packet);
	}
	av_free(pFrame);
	return 0;
}

int stream_component_open(VideoState *is, int stream_index) 
{
	AVFormatContext *pFormatCtx = is->pFormatCtx;
	AVCodecContext *codecCtx = NULL;
	AVCodec *codec = NULL;
	AVDictionary *optionsDict = NULL;
	SDL_AudioSpec wanted_spec, spec;

	if(stream_index < 0 || stream_index >= pFormatCtx->nb_streams) {
		return -1;
	}

	// Get a pointer to the codec context for the video stream
	codecCtx = pFormatCtx->streams[stream_index]->codec;

	if(codecCtx->codec_type == AVMEDIA_TYPE_AUDIO) 
	{
		// Set audio settings from codec info
		wanted_spec.freq = codecCtx->sample_rate;
		wanted_spec.format = AUDIO_S16SYS;
		wanted_spec.channels = codecCtx->channels;
		wanted_spec.silence = 0;
		wanted_spec.samples = SDL_AUDIO_BUFFER_SIZE;
		wanted_spec.callback = audio_callback;
		wanted_spec.userdata = is;

		if(SDL_OpenAudio(&wanted_spec, &spec) < 0) {
			fprintf(stderr, "SDL_OpenAudio: %s\n", SDL_GetError());
			return -1;
		}
		is->audio_hw_buf_size = spec.size;
	}
	codec = avcodec_find_decoder(codecCtx->codec_id);
	if(!codec || (avcodec_open2(codecCtx, codec, &optionsDict) < 0)) {
		fprintf(stderr, "Unsupported codec!\n");
		return -1;
	}

	switch(codecCtx->codec_type) 
	{
	case AVMEDIA_TYPE_AUDIO:
		is->audioStream = stream_index;
		is->audio_st = pFormatCtx->streams[stream_index];
		is->audio_buf_size = 0;
		is->audio_buf_index = 0;

		/* averaging filter for audio sync */
		is->audio_diff_avg_coef = exp(log(0.01 / AUDIO_DIFF_AVG_NB));
		is->audio_diff_avg_count = 0;
		/* Correct audio only if larger error than this */
		is->audio_diff_threshold = 2.0 * SDL_AUDIO_BUFFER_SIZE / codecCtx->sample_rate;

		memset(&is->audio_pkt, 0, sizeof(is->audio_pkt));
		packet_queue_init(&is->audioq);
		SDL_PauseAudio(0);
		break;

	case AVMEDIA_TYPE_VIDEO:
		is->videoStream = stream_index;
		is->video_st = pFormatCtx->streams[stream_index];

		is->frame_timer = (double)av_gettime() / 1000000.0;
		is->frame_last_delay = 40e-3;
		is->video_current_pts_time = av_gettime();

		packet_queue_init(&is->videoq);
		is->video_tid = SDL_CreateThread(video_thread, is);
		is->sws_ctx = sws_getContext ( is->video_st->codec->width, is->video_st->codec->height,
			is->video_st->codec->pix_fmt,
			is->video_st->codec->width, is->video_st->codec->height, PIX_FMT_YUV420P, 
			SWS_BILINEAR, NULL,  NULL,  NULL );
		codecCtx->get_buffer = our_get_buffer;
		codecCtx->release_buffer = our_release_buffer;
		break;

	default:
		break;
	}

	return 0;
}

int decode_interrupt_cb(void *opaque) 
{
	return (global_video_state && global_video_state->quit);
}

int decode_thread(void *arg) 
{
	VideoState *is = (VideoState *)arg;
	AVFormatContext *pFormatCtx = NULL;
	AVPacket pkt1, *packet = &pkt1;

	AVDictionary *io_dict = NULL;
	AVIOInterruptCB callback;

	int video_index = -1;
	int audio_index = -1;
	int i;

	is->videoStream=-1;
	is->audioStream=-1;

	global_video_state = is;
	// will interrupt blocking functions if we quit!
	callback.callback = decode_interrupt_cb;
	callback.opaque = is;
	if (avio_open2(&is->io_context, is->filename, 0, &callback, &io_dict))
	{
		fprintf(stderr, "Unable to open I/O for %s\n", is->filename);
		return -1;
	}

	// Open video file
	if(avformat_open_input(&pFormatCtx, is->filename, NULL, NULL)!=0)
		return -1; // Couldn't open file

	is->pFormatCtx = pFormatCtx;

	// Retrieve stream information
	if(avformat_find_stream_info(pFormatCtx, NULL)<0)
		return -1; // Couldn't find stream information

	// Dump information about file onto standard error
	av_dump_format(pFormatCtx, 0, is->filename, 0);

	// Find the first video stream
	for(i=0; i<pFormatCtx->nb_streams; i++) 
	{
		if(pFormatCtx->streams[i]->codec->codec_type==AVMEDIA_TYPE_VIDEO &&
			video_index < 0) {
				video_index=i;
		}
		if(pFormatCtx->streams[i]->codec->codec_type==AVMEDIA_TYPE_AUDIO &&
			audio_index < 0) {
				audio_index=i;
		}
	}
	if(audio_index >= 0) {
		stream_component_open(is, audio_index);
	}
	if(video_index >= 0) {
		stream_component_open(is, video_index);
	}   

	if(is->videoStream < 0 || is->audioStream < 0) {
		fprintf(stderr, "%s: could not open codecs\n", is->filename);
		goto fail;
	}

	// main decode loop

	for(;;) 
	{
		if(is->quit) {
			break;
		}
		// seek stuff goes here
		if(is->seek_req) {
			int stream_index= -1;
			int64_t seek_target = is->seek_pos;

			if     (is->videoStream >= 0) stream_index = is->videoStream;
			else if(is->audioStream >= 0) stream_index = is->audioStream;

			if(stream_index>=0){
				seek_target= av_rescale_q(seek_target, AV_TIME_BASE_Q, pFormatCtx->streams[stream_index]->time_base);
			}
			if(av_seek_frame(is->pFormatCtx, stream_index, seek_target, is->seek_flags) < 0) {
				fprintf(stderr, "%s: error while seeking\n", is->pFormatCtx->filename);
			} else {
				if(is->audioStream >= 0) {
					packet_queue_flush(&is->audioq);
					packet_queue_put(&is->audioq, &flush_pkt);
				}
				if(is->videoStream >= 0) {
					packet_queue_flush(&is->videoq);
					packet_queue_put(&is->videoq, &flush_pkt);
				}
			}
			is->seek_req = 0;
		}

		if(is->audioq.size > MAX_AUDIOQ_SIZE ||
			is->videoq.size > MAX_VIDEOQ_SIZE) {
				SDL_Delay(10);
				continue;
		}
		if(av_read_frame(is->pFormatCtx, packet) < 0) {
			if(is->pFormatCtx->pb->error == 0) {
				SDL_Delay(100); /* no error; wait for user input */
				continue;
			} else {
				break;
			}
		}
		// Is this a packet from the video stream?
		if(packet->stream_index == is->videoStream) {
			packet_queue_put(&is->videoq, packet);
		} else if(packet->stream_index == is->audioStream) {
			packet_queue_put(&is->audioq, packet);
		} else {
			av_free_packet(packet);
		}
	}
	/* all done - wait for it */
	while(!is->quit) {
		SDL_Delay(100);
	}
fail:
	{
		SDL_Event event;
		event.type = FF_QUIT_EVENT;
		event.user.data1 = is;
		SDL_PushEvent(&event);
	}
	return 0;
}

void stream_seek(VideoState *is, int64_t pos, int rel) 
{
	if(!is->seek_req) {
		is->seek_pos = pos;
		is->seek_flags = rel < 0 ? AVSEEK_FLAG_BACKWARD : 0;
		is->seek_req = 1;
	}
}

int ff_play_media_avx(const char *filein)
{
	SDL_Event       event;
	//double          pts;
	VideoState      *is;

	is = av_mallocz(sizeof(VideoState));

	// Register all formats and codecs
	av_register_all();

	if(SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER)) {
		fprintf(stderr, "Could not initialize SDL - %s\n", SDL_GetError());
		exit(1);
	}

	// Make a screen to put our video
#ifndef __DARWIN__
	screen = SDL_SetVideoMode(640, 480, 0, 0);
#else
	screen = SDL_SetVideoMode(640, 480, 24, 0);
#endif
	if(!screen) {
		fprintf(stderr, "SDL: could not set video mode - exiting\n");
		exit(1);
	}

	av_strlcpy(is->filename, argv[1], 1024);

	is->pictq_mutex = SDL_CreateMutex();
	is->pictq_cond = SDL_CreateCond();

	schedule_refresh(is, 40);

	is->av_sync_type = DEFAULT_AV_SYNC_TYPE;
	is->parse_tid = SDL_CreateThread(decode_thread, is);
	if(!is->parse_tid) {
		av_free(is);
		return -1;
	}

	av_init_packet(&flush_pkt);
	flush_pkt.data = (unsigned char *)"FLUSH";

	for(;;) {
		double incr, pos;
		SDL_WaitEvent(&event);

		switch(event.type) {
		case SDL_KEYDOWN:
			switch(event.key.keysym.sym) {
			case SDLK_LEFT:
				incr = -10.0;
				goto do_seek;
			case SDLK_RIGHT:
				incr = 10.0;
				goto do_seek;
			case SDLK_UP:
				incr = 60.0;
				goto do_seek;
			case SDLK_DOWN:
				incr = -60.0;
				goto do_seek;
do_seek:
				if(global_video_state) {
					pos = get_master_clock(global_video_state);
					pos += incr;
					stream_seek(global_video_state, (int64_t)(pos * AV_TIME_BASE), incr);
				}
				break;
			default:
				break;
			}
			break;
		case FF_QUIT_EVENT:
		case SDL_QUIT:
			is->quit = 1;
			/*
			* If the video has finished playing, then both the picture and
			* audio queues are waiting for more data.  Make them stop
			* waiting and terminate normally.
			*/
			SDL_CondSignal(is->audioq.cond);
			SDL_CondSignal(is->videoq.cond);
			SDL_Quit();
			exit(0);
			break;
		case FF_ALLOC_EVENT:
			alloc_picture(event.user.data1);
			break;
		case FF_REFRESH_EVENT:
			video_refresh_timer(event.user.data1);
			break;
		default:
			break;
		}
	}
	return 0;
}
